I always seem to take that highway in the other direction. I can make it to Gungadai Supercharger in my 1/2020 SR+ from Cooma without even overcharging it. Though I always stop for a nice long break on one of the three-phase destination chargers at Tumut River Brewing Co. It removes any hint of anxiety, even without sampling their brewed produce!
Wagga is a bit further off the range than Gundagai, so maybe consider that stop at Tumut for a full sit-down lunch.